Current carrying devices, such as cables, buss bars, wires and electrical connectors generate heat as current passes through them. This resistive heating generally limits the total current carrying capabilities of a system. Indeed, the current carrying capacity of the connector, cables, and buss bars is limited by the heat that can be dissipated through natural convection of the system. For a given level of current, under the amount that will cause a thermal runaway, the system will achieve a steady state temperature during operation. In the CSA (Canadian Standards Association) standard C22.2 No. 182.3-M1987 (R2009), the current associated with a temperature rise of 30° C., during steady state operation, determines the rated current capacity of a particular connector, cable, buss bar, wire or overall system.
Connectors tend to be the hottest part of the system since it has the greatest resistance per unit length and therefore great attention and research has been spent to find solutions to reduce the resistance of the separable interface of the connector. Consequently, reducing this resistance, and therefore the internal heating of the connector, has, historically, been the primary way to increase the current carrying capability of a system.